Stocks weighed down by Europe

Investors will be cautious heading into the week, amid a fresh bout of uncertainty over Europe and ongoing fiscal cliff negotiations in Washington.

Over the weekend, Italian Prime Minister Mario Monti unexpectedly announced plans to step down after parliament passes a national budget later this month.

The news sent Italian stocks plunging and the yield on the Italian 10-year bond rising to 4.82% from 4.5% last week. Investors are worried that Monti's resignation could throw a wrench into Italy's plans to bring down its high levels of debt.

"Monti has done a good job keeping Italy out of the cross hairs of Mr. Market, but the jig is up," said Marc Chandler, global head of currency strategy at Brown Brothers Harriman. "Investors fear rearguard action that will dismantle the reforms of Monti's unelected technocrat government."

Aside from Europe, U.S. investors will remain cautious as long as lawmakers fail to find consensus before the end of the year to avert the scheduled tax increases and spending cuts. Without a deal, the U.S. economy could fall back into a recession.

Investors are also waiting to see how the Federal Reserve acts later in the week.

The Fed's Federal Open Market Committee meeting on Tuesday and Wednesday could move markets. The central bank will have to decide the fate of one of its stimulus programs, Operation Twist, which is set to end this month.

Economists are expecting that the Fed will convert its program from swapping short-term bonds from long-term bonds into an outright bond purchase program.

On the corporate front, shares of Ingersoll-Rand (IR)rose after the company said it plans to spin off its commercial and residential security businesses into a new company. Ingersoll-Rand also announced a $2 billion share repurchase program and boosted its quarterly dividend.